Identification Documents
Identification documents (hereafter “ID documents”) play a critical role in today's society. One example of an ID document is an identification card (“ID card”). ID documents are used on a daily basis—to prove identity, to verify age, to access a secure area, to evidence driving privileges, to cash a check, and so on. Airplane passengers are required to show an ID document during check in, security screening and prior to boarding their flight. In addition, because we live in an ever-evolving cashless society, ID documents are used to make payments, access an automated teller machine (ATM), debit an account, or make a payment, etc.
(For the purposes of this disclosure, ID documents are broadly defined herein, and include, e.g., credit cards, bank cards, phone cards, passports, driver's licenses, network access cards, employee badges, debit cards, security cards, visas, immigration documentation, national ID cards, citizenship cards, social security cards, security badges, certificates, identification cards or documents, voter registration cards, police ID cards, border crossing cards, legal instruments, security clearance badges and cards, gun permits, gift certificates or cards, membership cards or badges, etc., etc. Also, the terms “document,” “card,” “badge” and “documentation” are used interchangeably throughout this patent application).
Many types of identification cards and documents, such as driving licenses, national or government identification cards, bank cards, credit cards, controlled access cards and smart cards, carry thereon certain items of information which relate to the identity of the bearer. Examples of such information include name, address, birth date, signature and photographic image; the cards or documents may in addition carry other so-called personalized or variable data (e.g., data specific to a particular card or document, for example an employee number) and so-called fixed or invariant data (e.g., data common to a large number of cards, for example the name of an employer). All of the cards described above will hereinafter be generically referred to as “ID documents”.
As those skilled in the art know, ID documents such as drivers licenses can contain additional information such as a photographic image, a bar code (which may contain information specific to the person whose image appears in the photographic image, and/or information that is the same from ID document to ID document), variable personal information, such as an address, signature, and/or birthdate, biometric information associated with the person whose image appears in the photographic image (e.g., a fingerprint), a magnetic stripe (which, for example, can be on the a side of the ID document that is opposite the side with the photographic image), and various security features, such as a security pattern (for example, a printed pattern comprising a tightly printed pattern of finely divided printed and unprinted areas in close proximity to each other, such as a fine-line printed security pattern as is used in the printing of banknote paper, stock certificates, and the like).
An exemplary ID document can comprise a substrate or core layer (which can be pre-printed), such as a light-colored, opaque material (e.g., polycarbonate, TESLIN (available from PPG Industries) polyvinyl chloride (PVC) material, etc). In certain instances and with certain printing or information forming technologies, variable or personalized data can be formed directly on the substrate or core layer. In other instances, the core layer may be coated and/or laminated with another material to enable printing or other methods of forming information. For example, the substrate or core layer can be laminated with a transparent material, such as clear polycarbonate or PVC to form a so-called “card blank”.
Certain technologies for forming or printing information may require further protection of the information, so an additional layer of transparent overlaminate can be coupled to the core layer or card blank and the information printed thereon, as is known by those skilled in the art. Illustrative examples of usable materials for overlaminates include polycarbonate, biaxially oriented polyester, or other optically clear durable plastic film.
Information, such as variable personal information (e.g., photographic information), can be formed on the card blank using one or more methods, such as laser xerography, Indigo, intaglio, laser engraving or marking, inket printing, thermal or mass transfer printing, dye diffusion thermal transfer (“D2T2”) printing, (described in commonly assigned U.S. Pat. No. 6,066,594, which is incorporated herein by reference in its entirety), etc. The information can, for example, comprise an indicium or indicia, such as the invariant or nonvarying information common to a large number of identification documents, for example the name and logo of the organization issuing the documents. The information may be formed by any known process capable of forming the indicium on the specific core material used.
Identification documents, such as ID cards, having printed background security patterns, designs or logos and identification data personal to the card bearer have been known and are described, for example, in U.S. Pat. No. 3,758,970, issued Sep. 18, 1973 to M. Annenberg; in Great Britain Pat. No. 1,472,581, issued to G. A. O. Gesellschaft Fur Automation Und Organisation mbH, published Mar. 10, 1976; in International Patent Application PCT/GB82/00150, published Nov. 25, 1982 as Publication No. WO 82/04149; in U.S. Pat. No. 4,653,775, issued Mar. 31, 1987 to T. Raphael, et al.; in U.S. Pat. No. 4,738,949, issued Apr. 19, 1988 to G. S. Sethi, et al.; and in U.S. Pat. No. 5,261,987, issued Nov. 16, 1993 to J. W. Luening, et al. All of the aforementioned documents are hereby incorporated by reference.
Identification documents of the types mentioned above can take a number of forms, depending on cost and desired features. For example, some ID documents comprise highly plasticized poly(vinyl chloride) or have a composite structure with polyester laminated to 0.5-2.0 mil (13-51 .mu.m) poly(vinyl chloride) film, which provides a suitable receiving layer for heat transferable dyes which form a photographic image, together with any variant or invariant data required for the identification of the bearer. These data are subsequently protected to varying degrees by clear, thin (0.125-0.250 mil, 3-6 .mu.m) overlay patches applied at the printhead, holographic hot stamp foils (0.125-0.250 mil 3-6 .mu.m), or a clear polyester laminate (0.5-10 mil, 13-254 .mu.m) supporting common security features. These last two types of protective foil or laminate sometimes are applied at a laminating station separate from the printhead. The choice of laminate dictates the degree of durability and security imparted to the system in protecting the image and other data.
One response to the problem of counterfeiting ID documents has involved the integration of verification features that are difficult to copy by hand or by machine, or which are manufactured using secure and/or difficult to obtain materials. One such verification feature is the use in the card of a signature of the card's issuer or bearer. Other verification features have involved, for example, the use of watermarks, biometric information, microprinting, covert materials or media (e.g., ultraviolet (UV) inks, infrared (IR) inks, fluorescent materials, phosphorescent materials), optically varying images, fine line details, validation patterns or marking, and polarizing stripes. These verification features are integrated into an identification card in various ways, as appreciated by those skilled in the art, and they may be visible or invisible (covert) in the finished card. If invisible, they can be detected by viewing the feature under conditions which render it visible. At least some of the verification features discussed above have been employed to help prevent and/or discourage counterfeiting.
Counterfeiting and/or Alteration of ID Documents
Despite the advances in the manufacture of ID documents, the ID document counterfeiter remains surprisingly resourceful. Improvements are needed to stay ahead of the counterfeiter. One counterfeiting technique involves a de-lamination attack. Consider an ID document that includes a printed substrate covered by a laminate layer. A de-lamination attack removes the laminate layer, sometimes with the aid of heat, to access information printed on the substrate. Once revealed, the counterfeiter can alter the printed information and reuse the substrate or laminate.
Some ID documents are susceptible to this type of attack. Consider the ID document including a substrate, ink applied to the substrate (or laminate layer) to convey information and a laminate layer covering the ink and substrate. Conventional inks generally include a strong adhesion to either a document substrate or to a laminate. A counterfeiter can use this design characteristic (adhesion) to his advantage. Upon de-lamination, the ink may adhere to the substrate layer or to a laminate layer. Regardless, the printed information is typically preserved on at least one layer and may be used again. (For example, if the ink adheres to a laminate, the counterfeiter can reuse the laminate. Or if the ink adheres to the substrate, the counterfeiter can perhaps alter the information by applying additional ink, or simply reuse the remaining information on the substrate).
U.S. Pat. No. 5,380,695, herein incorporated by reference, discloses an identification document designed to help deter intrusion attempts. With reference to FIG. 1, an image-receiving element 10 includes a support 12, a polymeric security layer 14 including printing, and an image-receiving layer 16. The polymeric security layer 14 is designed such that its cohesivity is less than its adhesivity for each layer that is contiguous thereto (layers 16 and 12b). A printed security pattern 18 is hopefully destroyed (into pieces 18a and 18b) through partitioning of the security layer 14 during an attempted de-lamination of the image-receiving layer 16 from the image-receiving element 12b (see FIG. 2).
Adhesives used with Overlaminate
Another type of delamination attack involves removal of the overlaminate. Over-laminate has been commonly applied as a protective layer for many types of security documents, such as identification cards, driver licenses, passports, and security badges. Over-laminates can be used to protect printed plastic cards (and the information formed on them) from abrasion, chemical attack such as plasticizer from the wallet, coffee, and bleach, from ultraviolet radiation, and from counterfeiting and tampering. Currently, most overlaminates consist of two layers: polyester base film and a thin layer of thermal active adhesive. With appropriate levels of heat and pressure, the overlaminate will bond to plastic card surface.
Although many overlaminates have been developed and produced for protection of ID documents, many existing laminates and/or adhesives used with them may have at one or more of the following limitations:
(a) Some overlaminate products are compatible only with certain types of other laminates and/or card blanks. For example, TBSN (available from Transilwrap Company, Inc., of Franklin Park, Ill.) generally is compatible only with PVC and cannot be used with polyester or polycarbonate.
(b) Some thermally active adhesives have a low glass transition temperature, which may cause film blocking and machine jam problems.
(c) Because the overlaminate is adhered onto the ID document surface by heat and pressure, reapplication of heat may enable intrusion into the ID document (e.g., cause complete or partial delamination of the overlaminate).
At least some embodiments of the invention help to overcome these and other disadvantages.
In one embodiment, we provide a composition for adhering a first article to a second article, the composition comprising a thermally active low Tg polymeric resin; and a multifunctional crystalline polymer. The thermally active low Tg polymeric resin can, for example, comprise 50-99% of the composition. The multifunctional crystalline polymer can, for example, comprise 1-50% of the composition. In one embodiment, the multifunctional crystalline polymer comprises 5-20% by weight of the composition. In one embodiment, the multifunctional crystalline polymer has a low molecular weight.
The thermally active low Tg polymeric resin can, for example, comprise at least one of a high molecular weight low Tg linear amorphous polyester, a polymeric plasticizer, VITEL 3650, polyacrylate, polyethylene vinylacrylate, polyester, and polyurethane.
The multifunctional crystalline polymer can, for example, comprise at least one of a di-functional polyester, a tri-functional polyester, a multi-functional polyester, polypropylene, polyamide, acetal, high density polyethylene, and VITEL 5833.
In one embodiment, the composition forms a plurality of crystals when heated at a temperature above a predetermined temperature and then cooled, wherein the predetermined temperature is a temperature lower than a standard lamination temperature, for example about 220 degrees Fahrenheit. The crystals can have a “snow flake” like appearance.
In another embodiment, we provide an identification document, comprising an information bearing layer, an adhesive layer, and a protective layer. The adhesive layer overlays at least a portion of the information-bearing layer and comprises a thermally active low Tg polymeric resin and a multifunctional crystalline polymer. The protective layer is coupled to the information-bearing layer via the adhesive layer. The adhesive layer, in one embodiment, is constructed and arranged such that subjecting the identification document to a temperature above a predetermined temperature causes a plurality of crystals to form in the adhesive layer. This crystal formation can be substantially irreversible.
The foregoing and other features and advantages of the present invention will become even more apparent with reference to the following detailed description and the accompanying drawings.
Of course, the drawings are not necessarily drawn to scale, with emphasis rather being placed upon illustrating the principles of the invention. In the drawings, like reference numbers indicate like elements or steps. Further, throughout this application, certain indicia, information, identification documents, data, etc., may be shown as having a particular cross sectional shape (e.g., rectangular) but that is provided by way of example and illustration only and is not limiting, nor is the shape intended to represent the actual resultant cross sectional shape that occurs during manufacturing of identification documents.